This invention relates to seismic marine exploration and more particularly to the refraction profile method of seismic exploration.
In general, there are two types of seismic exploration methods in which seismic energy is injected into the earth at a first surface location and upon traveling through the subsurface formations is detected at a second surface location. In one such method, the reflection method, seismic energy is directly reflected by the boundaries between the subsurface formations and returns to the earth's surface. In the other of such methods, the seismic energy meets such boundaries between subsurface formations at such an angle that it is refracted along a path that passes through the lower of two formations substantially parallel to the boundary between the formations. Upon emerging from the lower formation into the upper formation, the seismic energy is again refracted at the boundary with a similar angle to that at which it originally entered the lower formation from the upper formation. Upon returning to the surface, the seismic energy is recorded as seismic refraction signals.